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design pressure and the minimum test pressure for the high side of the system
shall be the high side design pressure, unless the high side of the system cannot
be isolated from the low side of the system in which case the entire system
shall be pressure tested to the low side design pressure.
b. The test pressure after removal of pressure source shall be maintained for at
least 1 h with no decrease of pressure indicated by the test gauge, with test
gauge resolution not exceeding 5% of the test pressure.
c. During the evacuation test, after achieving a vacuum level speci ed in the
manual or less, the refrigeration system shall be isolated from the vacuum pump
and the pressure shall not rise above 1500 microns within 10 min. The vacuum
pressure level shall be speci ed in the manual, and shall be the lessor of 500
microns or the value required for compliance with national and local codes and
standards, which may vary between residential, commercial, and industrial
buildings.
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eld-made refrigerant joints indoors shall be tightness tested according to the
following requirements: The test method shall have a sensitivity of 5 grams per
year of refrigerant or better under a pressure of at least 0,25 times the
maximum allowable pressure. No leak shall be detected.
3. Quali cation of workers
Any maintenance, service and repair operations must be required quali cation
shall only be carried out by competent persons that joined the training and
achieved competence should be documented by a certi cate. The training of
these procedures is carried out by national training organizations or
manufacturers that are accredited to teach the relevant national competency
standards that may be set in legislation. All training shall follow the ANNEX HH
requirements of UL 60335-2-40 4th Edition.
Examples for such working procedures are:
• breaking into the refrigerating circuit;
• opening of sealed components;
• opening of ventilated enclosures.
4. Ventilated area
Ensure that the area is in the open or that it is adequately ventilated before breaking
into the system or conducting any hot work. A degree of ventilation shall continue
during the period that the work is carried out. The ventilation should safely disperse
any released refrigerant and preferably expel it externally into the atmosphere.
5. Cabling
Check that cabling will not be subject to wear, corrosion, excessive pressure,
as compressors or fans.
6. Detection of ammable refrigerants
Under no circumstances shall potential sources of ignition be used in the searching
for or detection of refrigerant leaks. A halide torch (or any other detector using a
naked ame) shall not be used.
The following leak detection methods are deemed acceptable for refrigerant
systems. Electronic leak detectors may be used to detect refrigerant leaks but, in
the case of FLAMMABLE REFRIGERANTS, the sensitivity may not be adequate, or
may need re-calibration. (Detection equipment shall be calibrated in a refrigerant-
free area.) Ensure that the detector is not a potential source of ignition and is
suitable for the refrigerant used. Leak detection equipment shall be set at a
percentage of the LFL of the refrigerant and shall be calibrated to the refrigerant
employed, and the appropriate percentage of gas (25% maximum) is con rmed.
Leak detection uids are also suitable for use with most refrigerants but the use of
detergents containing chlorine shall be avoided as the chlorine may react with the
refrigerant and corrode the copper pipe-work.
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